Chair frame assembly

ABSTRACT

A chair frame assembly includes a frame, a plurality of mounting blocks, and a plurality of wheel devices. The frame includes a plurality of legs each having a coupling hole extending along a first longitudinal axis at a first acute angle to a vertical axis. Each coupling block includes an upper, insertion section having an engaging hole extending along a second longitudinal axis and a lower, coupling section extending along an axial axis at a second acute angle to the second longitudinal axis the same as the first acute angle. The insertion section of each coupling block is engaged in the coupling hole of one of the legs with the first longitudinal axis coincident with the axial axis and with the second longitudinal axis perpendicular to the ground. Each wheel device includes a wheel and an axle coupled in the engaging hole.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a chair frame assembly and, more particularly, to a chair frame assembly with improved verticality after assembly and with reliable support while prolonging the life of wheel devices thereof.

2. Description of the Related Art

A chair generally includes a chair frame with casters or wheels attached to a bottom of the chair frame to provide mobility. FIGS. 7 and 7A show a conventional chair frame assembly including a frame 1′, four coupling blocks 2′, and four wheel devices 3′. Frame 1′ includes a mounting section 11′ to which a seat and/or a backrest are mounted. Frame 1′ further includes four tubular legs 12′ extending downward and outward therefrom to increase the total area covered by legs 12′. Each leg 12′ includes a bend 121′ at a lower portion thereof. Bend 121′ extends in a vertical direction perpendicular to the ground a. Each coupling block 2′ is made of plastic material and includes an insertion section 21′ at an upper end thereof and a coupling section 22′ at a lower end thereof and coaxial with insertion section 21′. Insertion section 21′ is engaged in a lower end of one of bends 121′. Coupling section 22′ includes a longitudinal hole 221′. Each wheel device 3′ includes a wheel 32′ and an axle 31′ above wheel 32′ and received in longitudinal hole 221′ of one of coupling blocks 2′. However, formation of bends 121′ is inconvenient and increases the costs. Furthermore, the bends 121′ are not perpendicular to the ground a when the bending angle of bends 121′ went wrong due to manufacturing errors, such that an acute angle θ exists between a vertical axis c perpendicular to the ground a and a longitudinal axis b of each coupling block 2′. As a result, axle 31′ of each wheel device 3′ is shifted from vertical axis c and, thus, can not provide reliable support. Furthermore, wheel devices 3′ are liable to deform, break, and disengage from coupling blocks 2′.

BRIEF SUMMARY OF THE INVENTION

An objective of the present invention is to provide a chair frame assembly with improved verticality after assembly and with reliable support while prolonging the life of the wheel devices.

A chair frame assembly according to the preferred teachings of the present invention includes a frame having a mounting section and a plurality of legs extending downward and outward from the mounting section. Each leg includes a coupling hole in a lower end thereof and extending along a first longitudinal axis at a first acute angle to a vertical axis perpendicular to the ground. The lower end of each leg further includes a notch extending upward from a bottom edge thereof along the first longitudinal axis. The chair frame assembly further includes a plurality of coupling blocks each including an upper, insertion section and a lower, coupling section. The coupling section includes an engaging hole extending along a second longitudinal axis. The insertion section extends along an axial axis at a second acute angle to the second longitudinal axis of the engaging hole. The second acute angle is equal to the first acute angle. The insertion section further includes a tab. The insertion section of each coupling block is engaged in the coupling hole of one of the legs with the first longitudinal axis coincident with the axial axis, with the tab engaged in the notch, and with the second longitudinal axis perpendicular to the ground. The chair frame assembly further includes a plurality of wheel devices each including a wheel and an axle above the wheel. The axle of each wheel device is coupled in the engaging hole of one of the coupling blocks, and the axle is perpendicular to the ground when the wheel is located on the ground.

In the most preferred form, the insertion section includes a column in a center thereof and having a plurality of ribs on an outer periphery thereof. The column extends along the axial axis. The insertion section further includes an annular wall surrounding the column and spaced from the column by an annular groove. The tab extends inward from an inner periphery of the annular wall in a radial direction perpendicular to the axial axis. The ribs of the column of each coupling block is securely engaged with an inner periphery of the coupling hole of one of the legs by tight coupling, and the lower end of each leg is engaged in the annular groove of one of the coupling blocks.

The present invention will become clearer in light of the following detailed description of an illustrative embodiment of this invention described in connection with the drawings.

DESCRIPTION OF THE DRAWINGS

The illustrative embodiment may best be described by reference to the accompanying drawings where:

FIG. 1 shows a partly exploded, perspective view of a chair frame assembly according to the preferred teachings of the present invention.

FIG. 1A shows an enlarged view of a coupling block of the chair frame assembly of FIG. 1.

FIG. 2 shows a partial, perspective view of the chair frame assembly of FIG. 1.

FIG. 3 shows a partial, partly cross-sectioned, exploded, perspective view of the chair frame assembly of FIG. 1.

FIG. 4 shows a partial, cross-sectional view of the chair frame assembly of FIG. 1 according to section line A-A of FIG. 2.

FIG. 5 shows a partial, cross-sectional view of the chair frame assembly of FIG. 1 according to section line B-B of FIG. 2.

FIG. 6 shows a side view of the chair frame assembly of FIG. 1.

FIG. 7 shows a side view of a conventional chair frame assembly.

FIG. 7A shows an enlarged view of a circled portion of the chair frame assembly of FIG. 7.

All figures are drawn for ease of explanation of the basic teachings of the present invention only; the extensions of the figures with respect to number, position, relationship, and dimensions of the parts to form the preferred embodiment will be explained or will be within the skill of the art after the following teachings of the present invention have been read and understood. Further, the exact dimensions and dimensional proportions to conform to specific force, weight, strength, and similar requirements will likewise be within the skill of the art after the following teachings of the present invention have been read and understood.

DETAILED DESCRIPTION OF THE INVENTION

A chair frame assembly according to the preferred teachings of the present invention is shown in the drawings and generally includes a frame 1, four coupling blocks 2, and four wheel devices 3. Frame 1 includes a mounting section 11 to which a seat and/or a backrest are mounted. Frame 1 further includes four legs 12 extending downward and outward from mounting section 11, so that each leg 12 extends along a longitudinal axis e at an acute angle θ1 (FIG. 4) to a vertical axis d perpendicular to the ground a (FIG. 6). Each leg 12 is tubular and includes a coupling hole 121 in a lower end thereof and extending along longitudinal axis e. The lower end of each leg 12 further includes a notch 122 extending upward from a bottom edge thereof along longitudinal axis e.

Each coupling block 2 includes an upper, insertion section 21 and a lower, coupling section 22. Coupling section 22 includes an engaging hole 221 extending along a longitudinal axis. Insertion section 21 includes a column 211 in a center thereof and having a plurality of ribs 212 on an outer periphery thereof. Column 211 extends along an axial axis at an acute angle θ1 to the longitudinal axis of engaging hole 221 (FIG. 4). Insertion section 21 further includes an annular wall 213 surrounding column 211 and spaced from column 211 by an annular groove 214. A tab 215 extends inward from an inner periphery of annular wall 213 in a radial direction perpendicular to the axial axis of the column 211. Each mounting block 2 is coupled with coupling hole 121 of one of legs 12 with ribs 212 of column 211 securely engaged with an inner periphery of coupling hole 121 by tight coupling, with the lower end of leg 12 engaged in annular groove 214, and with tab 215 engaged in notch 122, preventing rotation of coupling block 2 relative to leg 12. After assembly, the axial axis of column 211 of each coupling block 2 is coincident with longitudinal axis e of coupling hole 121 of one of legs 12, and the longitudinal axis of engaging hole 221 of coupling section 22 of each mounting block 2 is coincident with vertical axis d.

Each wheel device 3 includes a caster or wheel 32 and an axle 31 above wheel 31. Axle 31 is coupled in engaging hole 221 of one of coupling blocks 2. After assembly, axle 31 of each wheel device 3 is perpendicular to the ground a. Furthermore, mounting blocks 2 do not rotate relative to legs 12 so that the angel between axles 31 and the ground a will not change. Reliable support is, thus, provided.

Legs 12 of the chair frame assembly according to the preferred teachings of the present invention need no bending and, thus, reduce the manufacturing costs and avoid manufacturing errors that may lead to damage to wheel devices 3. The life of wheel devices 3 is prolonged. Furthermore, the verticality of axles 31 relative to the ground a is assured to provide reliable support. It can be appreciated that the legs 12 can be arcuate instead of rectilinear, as along as coupling hole 121 extends along longitudinal axis e.

Thus since the invention disclosed herein may be embodied in other specific forms without departing from the spirit or general characteristics thereof, some of which forms have been indicated, the embodiments described herein are to be considered in all respects illustrative and not restrictive. The scope of the invention is to be indicated by the appended claims, rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are intended to be embraced therein. 

1. A chair frame assembly comprising: a frame including a mounting section and a plurality of legs extending downward and outward from the mounting section, with each of the plurality of legs including a coupling hole in a lower end thereof and extending along a first longitudinal axis at a first acute angle to a vertical axis perpendicular to a ground, with the lower end of each of the plurality of legs further including a notch extending upward from a bottom edge thereof along the first longitudinal axis; a plurality of coupling blocks each including an upper, insertion section and a lower, coupling section, with the coupling section including an engaging hole extending along a second longitudinal axis, with the insertion section extending along an axial axis at a second acute angle to the second longitudinal axis of the engaging hole, with the second acute angle being equal to the first acute angle, with the insertion section further including a tab, with the insertion section of each of the plurality of coupling blocks being engaged in the coupling hole of one of the plurality of legs with the first longitudinal axis coincident with the axial axis, with the tab engaged in the notch, and with the second longitudinal axis perpendicular to the ground; and a plurality of wheel devices each including a wheel and an axle above the wheel, with the axle of each of the plurality of wheel devices being coupled in the engaging hole of one of the plurality of coupling blocks, with the axle being perpendicular to the ground when the wheel is located on the ground.
 2. The chair frame assembly as claimed in claim 1, with the insertion section including a column in a center thereof and having a plurality of ribs on an outer periphery thereof, with the column extending along the axial axis, with the insertion section further including an annular wall surrounding the column and spaced from the column by an annular groove, with the tab extending inward from an inner periphery of the annular wall in a radial direction perpendicular to the axial axis, with the plurality of ribs of the column being securely engaged with an inner periphery of the coupling hole of one of the plurality of legs by tight coupling, and with the lower end of each of the plurality of legs engaged in the annular groove of one of the plurality of coupling blocks. 